Definition of dewar in English:

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Pronunciation: /ˈd(y)o͞owər/


A double-walled flask of metal or silvered glass with a vacuum between the walls, used to hold liquids at well below ambient temperature.
Example sentences
  • However, only the sample dewar was filled with liquid nitrogen.
  • Liquid helium will boil off constantly through a special porous plug in the dewar to maintain the science probe at its required temperature for up to 18 months.
  • But in 1999 the project experienced major development problems when the large thermos bottle, called a dewar, which holds the supercold helium surrounding the instruments, did not cool down as quickly as expected.


Late 19th century: named after Sir James Dewar (see Dewar, Sir James).

For editors and proofreaders

Syllabification: dew·ar

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